Counterbalance for vertically sliding doors



p 1942- H. c. BLODGETT 2,294,360

COUNTERBALANCE FOR VERTICALLY SLIDING DOORS Filed July 5, 19.38 3 Sheets-Sheet 1 w 4 10 5 J7 I1 15 INVENTOR. BY fierfierf Q fl/oooe/f ATTORNEYS Sept. 1, 1942. H. c. BLODGETT COUNTERBALANCE FOR VERTICALLY SLIDING DOORS a Sheets-Sheet 2 Filed July 5, 1938 1 Ft Z E p 1942- H. c. BLODGETT 2,294,360

COUNTERBALANCE FOR VERTICALLY SLI-DING DOORS Filed July 5, 19558 3 Sheets-Sheet 5 INVENT OR.

BY Mr W ATTORNEY5 terbalancing a sliding door.

Patented Sept. 1,-1942 UNITED STATES PATENT. OFFICE COUNTERBALANCE FOR VERTICALLY SLIDING DOORS Herbert Cady Blodgett, Hartford City, Ind., as-

signor to Overhead Door Corporation, Hartford City, Ind., a corporation of Indiana Application July 5, 1938, Serial No. 217,477

9 Claims.

Third, to provide a device of the type described which is economically and cheaply manufactured due to the simplicity of its parts.

Fourth, to provide a counterbalance mechanism which may be easily installed and accurately adjusted for the particular door and installation.

Fifth, to provide a device of the type described which can be manufactured and shipped as a unit and which is ready for immediate assembly on location at the time that the door is being erected.

Sixth, to provide a mechanism of very strong construction requiring a minimum of service throughout its life.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is defined and pointed out in the claims.

A preferred embodiment of the invention is illustrated in the accompanying drawings, in which:

Fig. 1 is an elevation view of the counterbalancing device of the invention showing the same assembled adjacent the frame of the door and operatively connected to the door, parts being sectioned and broken away.

Fig. 2 is an enlarged fragmentary view illustrating a detail of construction.

Fig. 3 is a fragmentary view in central longitudinal section on line 33 of Figs. 4 and 5, illustrating details of construction of the counterbalancing device.

Fig. 4 is a fragmentary view in side elevation of the device in operative position relative to a door frame.

Fig. 5 is a fragmentary side view in section on line 5-5 of Fig. 3 illustrating a detail of construction.

Fig. 6 is a side view in section on line 6'G of Fig. 7, illustrating a detail of construction of the invention.

Fig. 7 is an enlarged fragmentary view in iongitudinal section along line 1-1 of Fig. 6.

Figs. 8 and 9 are side views illustrating component parts of an adjustable door counterbalancing drum.

Fig. 10 is a view in central longitudinal section illustrating a modified embodiment of an adjustable drum part.

Referring to the drawings, the reference numeral I in general indicates a vertically sliding door of the multiple hinge panel type which is provided with guide rollers 2 traveling in guide tracks 3, the tracks being angled as indicated in Fig. 4.

The counterbalance device which forms the subject matter of the present invention is indicated in general by the reference numeral 4. This counterbalance device, in the embodiment illustrated, comprises an elongated tubular shaft or drum 5 having at each end thereof centrally apertured drum end members or blocks 5 and I. A suitable coiled torsion spring 8 is employed as a means for storing energy to counterbalance the door as it is moved from lowered to open position, and vice versa. This coiled spring is anchored to the drum 5 at one end by means of a plug-like spring support 9 which is secured to the drum by means of the pin or bolt III. This spring support 9 is externally threaded and the spring is mounted thereon by screwing the support and spring together. The opposite end of the spring 8 is threaded upon a similar spring supporting member II. This spring support II has a square or non-circular longitudinal bore or hole l2 which receives the correspondingly sectioned torsion rod or spindle l3, the spring support being preferably upset at l5 as a further securing means.

Adjacent the outer end of the rod or spindle I3 I secure by means of a pin I6 aflanged sleeve l1. Between this sleeve and the drum end member is a ball bearing designated generally by the numeral IS, the outer ways of this ball bearing being pressed into the bore IS in the drum end member 6.

The counterbalancing mechanism 4 is supported at its ends on a pair of angle iron brackets 20 and 2|. The bracket 20 adjacent the drum end member I carries a pivot pin or trunnion 22 which is shouldered and has the reduced end thereof threaded at 23 to receive a locking nut 24. A suitable ball bearing 25 is pressed into 1 the drum end member 1 and in operative position is supported by the trunnion 22 to rotatabiy mount the dead end of the drum, i. e., the end to the left as viewed in Figs. 1 and 3. This ball bearing has projecting radial and axial flanges 26, 21 for engaging the end member I and for spacing the drum from the bracket 20, respectively.

In order to removably support the end of the counterbalancing device adjacent the bracket 2 I, I provide a vertical rectangular slot 28 in the said bracket, see Fig. 2, and I pivotally mount on the bracket a catch or retaining plate 29 having a generally square slot 38 therein disposed transversely of the slot 28. The last named slot is sufliciently wide to permit rotation of the drum to store up or release energy in spring 8 and the slot 38 in the retaining plate 28 thereafter engages the square torsion rod I3 and prevents ,rotation thereof. Thus it is apparent that the end member I may be disposed on the trunnion 22 and readily removed therefrom. The foregoing constitutes a simple though efiective releasable means for supporting the counterbalance device in position for operation.

In order to facilitate assembly of the device, I provide the projecting end 3I of the spindle I3 with a suitable transverse bore 32 through which a pin, nail, or other pulling member may be inserted to draw the support I I axially of the drum 5. Thus the spindle I3 may be drawn to the right as viewed in Fig. 3 in order to stretch the spring axially within the drum so that the coils thereof will not lie together and create friction when the spring coils and uncoils. With the spindle I3 drawn axially as described, the drum en'd memher 5 is placed thereon in proper position and the retaining sleeve I1 is pinned in position on the spindle to the right of the disk by the pin I5. By now releasing the tension upon the spindle I3, the retaining sleeve I'I slides into position in the ball bearing I8 due to the tension exerted by the spring 8, and the drum end member 5 is .likewise drawn into the end of the drum and held securely therein.

At the opposite end of the drum the end memher I may be rigidly secured thereto by notching the flange 33 thereof in the manner indicated by the reference numeral 34, see Fig. 5, and by correspondingly cutting away the end of the drum 5 at intervals to provide four tabs 36 which may be alined with notches 34 and bent over radially on the outer side of the end member, thus rigidly locking the drum and its end member together.

The cables 31, which are to be trained about the drum 5 in the manner illustrated in Fig. 3, are connected to the bottom of the door I by means of the plates 40 secured to the cables by clips ll and having holes 42, in the manner illustrated in Figs. 1 and 3. The cables may be attached to the drum 5 immediately adjacent the end member flanges in any suitable manner. In Fig. 3 I illustrate a preferred expedient for this purpose wherein a suitable aperture or notch is cut in the end of the drum at 38 and the cable passed therethrough and wound directly around the drum, lbeing frictionally gripped between the end member and the drlnn and with a clamp or :band 39 securedto the inner end thereof to prevent its escape.

As illustrated in Figs. 1 and 3, a line between the point of connection of the cables 31 with the door on the one hand and to the drum 5 on the other hand is inclined to the vertical in order that the cable will be wound level on the drum. It is emphasized that the drum end members 5, I should be placed as close as possible to the supporting brackets 20, 2I without actually interferring therewith in order to obtain as great a length on the drum as possible for the winding of the cable. In other words, the winding of the cables must take place as near the ends of the drum as possible, since with the door in fully open or retracted position-there is the greatest amount of cable wound on the drum. Accordingly, to the end that the cable will be fully wound on the drum before the cable reaches a vertical position, while still conserving in material to the greatest extent, it is advisable to construct the elements in the relation which I have shown, 1. e., conserving the space between the supporting brackets and the end members as much as possible. I. am aware that it is possible to restrict the axial space occupied by the cable on the drum by. increasing the diameter of the 'latter. However, it is well to hold the outer diameter of the drum as small as possible inasmuch as the power of the spring required to operate the same is thereby lessened, which is a point Ibearing directly on the economy of the device. g

The manner of assembling the counterbalance on the door should be apparent from the foregoing description. The dead end is first thrust on the stud 22 and the adjustable end dropped in the notch 28, and the ends of the cables 31 are attached to the respective lower comers of the door. Lowering of the door to closed position thereafter tensions the spring 8, and should it be desired to make an adjustment in this tension it may be done by releasing the rod I3 y from the slot 28.

It sometimes happens that in the erection of or plane away a portion of the lower section or rail of the door in order to permit the door to fit tightly on the floor. In such cases it is necessary to readjust the point of attachment of the cable to the door or to make other compensating provisions.

In Figs. 1, 3, 6, 7, 8 and 9 I illustrate a preferred structure for obtaining the compensation referred to by adjusting the ends of the drum 5 relative to one another to take up differences in tension between the two cables and give them an even lift on the door. In this modification the drum 5 is constructed of two parts having a telescoping fit, the part 5I being provided with an inner coupling tube 52 which is bolted thereto by bolt III or otherwise secured, and which slidably and telescopingly receives the part 53. The part 53 is slotted peripherally as indicated by the reference numeral 54 and elongated bolts 55 extend through the part 53 and coupling 52, the parts being locked together by the tightening nut 55. The block 51 of wood is inserted in coupling 52 and is apertured to receive bolts 55, thus serving to prevent .crushing of the drum when nuts 55 are taken up. Y

By the foregoing means it is apparent that any difference in length of the cables occasioned by cutting or trimming the door to bring it flush with the floor as indicated at 43 is compensated for by effecting relative rotation of the parts 5|, 53 and thereafter tightening the nut 55. In addition, if desired, the length of the drum 5 may be readily altered on the job by cutting ofi the part '53 or the tube 52 as desired, or the drum may be lengthened =by elongating these parts.

In Fig. '10 I indicate a modified embodiment of the foregoing structure wherein the drum part 5I and coupling 52 are made integral by reducing the diameter of a tube 58 to provide an integral coupling neck 59 to which a part 53 may b attached as described above.

I have illustrated and described my invention in embodiments which are very practical. I have notattempted to illustrate or describe other embodiments or adaptations as it is believed this disclosure will enable those skilled in the art to embody or adapt my improvements as may be desired.

Having th'us described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In-a counterbalancing mechanism for vertically sliding doors, the combination with a tubular drum comprising telescoping relatively rotatable sections normally in fixed angular relation, a coiled counterbalancing spring housed within said drum, a supporting spindle for one end of said drum to which one end of said spring is attached, a support within said drum for the other end of said spring, means for securing said drum sections in their rotatably adjusted positions relative to each other comprising a bolt ar-' ranged through the telescoped ends of said sections and said spring support, at least one of said sections having an elongated recess receiving said bolt for angular adjustment relative thereto, and door attaching cables independently attachable to a door and adapted to wind one on each of said drum sections whereby the drum sections may be rotatively adjusted relative to each other to compensate for variations in the lengths of the cables or variations in their point of attachment to the door, said telescoped'drum sections when secured together completely enclosing said spring and constituting the sole means for transmitting torque along and between the ends of the drum.

2. In a counterbalancing mechanism for vertically sliding doors, the combination with a tubular drum comprising telescoping relatively rotatable sections normally in fixed angular relation, a coiled counterbalancing spring housed within said drum, a supporting spindle for one end of said drum to which one end of said spring is attached, a support within said drum forthe other end of said spring, means for securing said drum sections in their rotatably adjusted positions relative to each other comprising a bolt arranged through the telescoped ends of said sections and said spring support, at least one of said sections having an elongated recess receiving said bolt for angular adjustment relative thereto, and door attaching cables adapted to wind one on each of said drum sections whereby the drum sections may be rotatively adjusted relative to each other to compensate for variations in the lengths of the cables, said telescoped drum sections when secured together completely enclosing said spring and constituting the sole means for transmitting torque along and between the ends of the drum.

3. In a counterbalancing mechanism for vertically sliding doors, the combination with a tubular drum comprising axially mounted and telescoped sections connected for rotative adjustment relative to each other but normally in angularly fixed relation, a coiled counterbalancing spring housed within said drum, a supporting spindle for one end of said drum to which one end of said spring is attached, a support Within said drum for the other end of said spring, means coacting with said sections at the zone of overlap thereof for securing said drum sections in their rotatably adjusted positions, and door attaching cables adapted to wind one on each of said drum sections whereby the drum sections may be rotatively adjusted relative to each other to compensate for variations in the lengths of the cables as attached to a door, said telescoped drum sections when secured together completely enclosing said spring and constituting the sole means for transmitting torque along and between the ends of the drum. g

4. In a counterbalancing mechanism for a vertically sliding door, a winding drum having coaxial tubular portions telescoping with one another and normally disposed in fixed angular relation to one another, a pair of cable elements each attached at one end to said door and at the other end to the respective drum portions and wound on the latter, torsion Winding means in said drums secured to the latter and to a fixed anchoring member to tension said cable elements, and means for compensating for inequalities in the tension of said cable elements, comprising means at the zone of overlap of said drum portions for shifting one portion relative to the other and locking said portions in their adjusted position in fixed angular relation to one another, said drum sections constituting the sole means for transmitting torque along the drum from one end thereof to the other.

5. In a counterbalancing mechanism for a vertically sliding door, a winding drum having coaxial tubular portions telescoping with one another and normally disposed in fixed angular relation to one another, a pair of cable elements each attached at one end to said door and at the other end to the respective drum portions and wound on the latter, and means for compensating for inequalities in the tension of said cable elements, comprising means at the zone of overlap of said drum portions for shifting one portion relative to the other and locking said portions in their adjusted position in fixed angular relation to one another, said drum sections constituting the sole means for transmitting torque along the drum from one end thereof to the other. a

6. A counterbalance for a vertically sliding door, including an elongated drum of substantial diameter adapted to be mounted above the door to extend from side to side thereof, said drum comprising coacting axially overlapped and telescoped drum sections normally in angularly fixed relation and having manually adjustable means at the area of overlap normally locking the same in said relation but adjustable to permit relative rotation of the sections when desired, door tensioning cables fixedly connected to and wound around said respective sections adjacent either ,end of said drum, said cables being adapted to be connected to opposite sides of the door below the drum and the relative rotation of said sections enabling adjustment of said cables as to efiective length relative to one another, a fixed anchoring member disposed internally of and adjacent one end of said drum, drum supporting means at one end of the drum including means mounting said drum for rotation relative to said member, a rotatable anchoring member disposed internally of said drum in substantially spaced relation to the first named member, means securing said drum to said rotatable anchoring member for rotation therewith, drum supporting means at the other end of the drum including means rotatably mounting said last named anchoring member, and a coiled torsion spring disposed internally and longitudinally of saidv drum in fixed anchoring engagement with said anchoring members, whereby tensioning of said cables and rotation of the drum causes rotation of one of said members relative to the others with 1 resultant torsioning of the spring.

7. A counterbalance for a vertically sliding door, including an elongated drum of substantial diameter adapted to be mounted above the door 2,294,:3oo' f a end of said drum, said cables being adapted to be connected to opposite sides of the door below the drum and the relative rotation of said sections enabling adjustment of said cables as to eflective tions/enabling adjustment of said cables as to effective length relative to one another, a fixed anchoring member disposed internally of and adjacent'one end of said drum, means mounting said drum for rotation relative to said member, a rotatable anchoring member disposed internally of said drum in substantially spaced relation to the first named member, means securing said drum to said rotatable anchoring member for rotation therewith, and a coiled torsion spring disposed internally and longitudinallyof said drum in fixed anchoring engagement with said anchoring members, whereby tensioning of said cables and rotation of the drum causes rotation of one of said members relative to the others with resultant torsioning of the spring.

8. A counterbalance for a vertically sliding door, including an elongated drum of substantial diameter adapted to be mounted above the door to extend from side to side thereof, said drum comprising coacting axially overlapped and telescoped drum sections normally in angularly'fixed relation and having manually. adjustable means at the area of overlap normally locking the same in said relation but adjustable to permit relative rotation of the sections when 'desired, door tensioning cables fixedly connected to and wound around said respective sections adjacent either length relative to one another, a fixed anchoring member disposed internally of said drum, means mounting said drum for rotation relative to said member, a rotatable anchoring member dispos d internally of said drum, means securing said drum to said rotatable anchoring member for rotation therewith, and a coiled torsion'spring'in fixed anchoring engagement with said anchoring members, whereby tensioning of said cables and rotation of the drum causes rotation of one of said members relative to the others with resultant torsioning oi the spring.

9. A counterbalance for a vertically sliding I door, including an elongated drum of substantial diameter adapted to be mounted above the door to extend from side to side thereof, aid drum comprising coacting axially, overlapped and telescoped drum sections normally in angularly fixed relation and having manually adjustable means normally locking the same in said relation but adjustable to permit relative rotation of the sections when desired, door tensioning cables fixedly connected to and wound around said respective sections, said cables being adapted to be connected to opposite sides of the door below the drum and the relative rotation of said secrelative to said member, a rotatable anchoring I member disposed internally of said drum, means securing said drum to said rotatable anchoring member for rotation therewith, and a coiledtori sion spring in fixed anchoring engagement with said' anchoring members, whereby tensioning'of said cables and rotation of the drum causes rotation of one of said members relative to the others with resultant torsioning oithe spring.

' HERBERT CADY BLODGEI'I. 

